Telegraph exchange system



g- 1930. A. F. CONNERY' TELEGRAPH EXCHANGE SYSTEM.

Filed Jan. 4, 1928 2 Sheets-Sheet 1 ALDER F CONNERY 3mm Filed Jan. 4, 1928 Y 2 Sheets-Sheet 2 III-lulllll- ALDERF. CONNERY 3. m

Patented Aug. 26, 1930 UNITED STATES PATENT OFFICE ALDER F. CONNERY, 0F BROOKLYN, NEW YORK, ASSIGNOB TO POSTAL'TELEGRAPH- CABLE COMPANY, 01 -NEW YORK, N. Y., A CORPORATION OF CONNECTICUT TELEGRAPH EXCHANGE SYSTEM Application filed January 4, 1928. Serial No. 244,393.

This invention relates to printing telegraphy and particularly to printing telegraph exchange systems used in connection with printing telegraph apparatus of the well known start-stop type.

Printing telegraph machines of the startstop type are well known in the art and are branch ofllces. When a large number of cir cuits are involved it is uneconomical and inconvenient to have so many machines at the main ofiice and it is desirable to concentrate the operation at the main oflice on a few machines and provide switching'means for connecting any one of the branch ofiice machines to an idle machine at the main oflice.

The arrangement heretofore used for accomplishing this purpose has been similar to that. in use on the widely used Morse telegraph system. One objection to the Morse telegraph switching arrangement is that it does not furnish a means of stopping the driving motor of the branch ofiice machine and thereby eliminate wear and noise when not in use. A further objection is that it is possible for the operator at the branch oflice to-cause loss or delay to messages by sending them to the wind. By this is meant the transmission of signals over a line to which no machine is connected at the main'oflice.

The object of-my invention is to overcome the foregoing objections to the Morse telegraph system. I accomplish this object by causing the branch office machine to be inoperative except when it is properly connected to a main ofiice machine and also arrange to have the driving motors on both main and branch machines operate only when the machines are in use. 7

Referring to the drawings, Fig. 1 is a diagram of the electrical circuits of this invention. The drawing shows only one branch busy. I switchboard and is for the purpose of informoflice machine and one main office machine, but it should be understood that there will be a plurality of branch oflice machines which may be connected to any one of one or more main ofiice machines. Fig. 2 shows how this invention may be used in connection with multiple pin jacks at the'main oflice. In the drawings like parts are represented by like numerals.

I will now proceed to describe my invention.

Referring to Fig. 1. The operating magnet of the branch oflice printer is shown at 1. The transmitting keyboard contacts of the branch office machine are shown at 2. At 3 is shown a non-polarized or neutral relay whose winding may become short circuited by the contacts of 4 which is a polarized relay. Relay 4 is equipped with a biasing spring and is connected in the line so that when either positive current or no current is supplied from the main ofiice its contacts keep the windings :of relay 3 shunted out. The transmission of messages is accomplished by making and breaking the positive line current supplied from the main ofiice and under these conditions relay 3 is unoperated because its windings are short-circuited and the current to driving motor 5 is therefore uninterrupted. When it is desired to stop motor 5 negative current is supplied from the main office. Operation of polarized relay 4 removes the shunt from relay 3 which becomes energized and interrupts the current to driving motor 5. Negative current is normally supplied from the main oflice when the branch office machine is not in use. The line relay at the main office is shown at 6. the line jack at 7 and the indicator lamp at 8. The indicator lamp is illuminated when the branch oflice wishes to secure a connection with a main oflice machine. The pin plug 9 is associated with the main office machine. The indicator lamps 10 and 11 indicate when the main ofiice, operator is not The lamp 10 appears on the shelf of the ingthe switchboard operator whether or not the main office operator is busy. Lamp 11 is located at the main office operators position and its purpose is to give the operator an indication that the non-busy signal is appearing at the switchboard on lamp 10. In series with the pin plug 9 is the operating magnet 12 of the main ofiice printer, the transmittings eyboard contacts 13 and relay 14. The jac ,relays, etc., in Fi 1 have been shown in the idle position. ssume now that the branch ofiice operator desires to'send to the main office. The branch office operator depresses key 15 for a moment and thereby opens the line. This de-energizes winding 16 of relay 6 which falls back. Relay tongue 17 in falling back shunts out winding 16 and prevents it being energized when the line circuit recloses. Relay tongue 18 completes the circuit through lamp 8 which is illuminated until the switchboard attendant responds and inserts a plug and cord thereby connecting the branch ofiice with a machine at the main oflice.

The insertion of plug 9 in jack 7 will open the lamp circuit 8. The circuit from negat ve battery 19 will be opened and the positive line battery 20 will now be supplied through relay winding 21 through sleeve of jack 7 and plug 9 through 12, 13 and 14, through tip of plug 9 and jack 7 and through the line to the branch ofiice machine. The positive current now supplied from the main office starts the branch office machine as previously explained. Relay 6 is energized and operates in response to the line signals. The insertion of plug 9 in jack 7 also starts the main office machine in the followin manner. 'When the plug is inserted in the ack, relay 14 pulls up and causes a momentary current nnpulse through condenser 26 to flow through winding 22 of relay 23. Relay 23 locks up through its winding 24 and extinguishes lamps 10 and 11, and at the same time through its left tongue and contact closes the circuit to motor,

25 which starts. Messages may now be 8X changed by the main and branch office operators.

The main office operator will initiate the termination of the connection by momentarily depressing key 28 which unlocks relay 23 which falls back and stops motor 25 and illuminates lamps 10 and 11. The switchboard attendant observes that lamp 10 is illuminated and removes the plug from the line jack. The removal of the plug causes nega-' tive battery to be applied to the line which stops the motor of the branch office machine. A situation might occur, however, in which the main ofiice operator made the erroneous conclusion that the branch ofiice operator had no further messages to send and therefore depressed key 28 which stopped the main office printer motor and illuminated the lamp 10 at the switchboard. The branch ofiice operator would be unaware that the main office machine had been stopped and might decide to send some more messages. Provided the branch office operator resumes sending before the cord has been pulled down at the board no loss of messages can occur because the first signal sent from the branch ofiice will cause relay 14 to operate and generate an impulse which will again lock up relay 23, start the motor and extinguish lamp 10 at the switchboard. It would be impossible of course for the branch oifice operator to transmit after the cord and plug had been pulled out of the line jack at the switchboard since the branch machine would be completely stopped by reason of the reversed current from the main office. In this case it would be necessary for the branch ofiice operator to again signal the switchboard operator by depressing key 15.

In some installations of this system it might be desirable to eliminate the need for the switchboard operator and permit the main office printer operators to do their own switching. If there are several operators at the main oflice they will not all have easy access to line jack 7 so it will be necessary to multiple the line jacks and lamps so as to appear in different locations where one of them may be reached conveniently by any operator. Fig. 2 shows how this may be done with three line jacks and lamps. It will be readily seen that this scheme will permit using as many line jacks and lamps in multiple as required.

Although the invention has been disclosed and described in conjunction with a particular type of system it is, of course, obvious that various departures may be made without departing from the spirit and scope of the present invention.

I claim:

1. In a printing telegraph exchange sys tem, a main station, a plurality of branch stations, means for establishing a printing telegraph circuit between said main station and any one of said branch stations, means at said main station for rendering inoperative the main station printing telegraph apparatus and means at said main station responsive to signalling impulses from the branch station to render operative said main station printing telegraph apparatus.

2. In a printing telegraph switching system, a plurality of branch telegraph stations each provided with a receiving printer and transmitter, a line conductor connected with each branch telegraph station for the transmission of messages, means at the central telegraph office operated from the branch station over said line conductor for indicating when the branch station requires a connection with a central office printer and means responsive to said connection for controlling the driving motor at the branch telegraph station, control of said driving motor being eflected over said line conductor by the change in polarity of line potential, means for rendering the central ofiice printing telegraph machine inoperative and means automatically controlled by the receipt of printer signals to render said ing at a central oflice,

' oflice printing telegraph machine with any of said subscribers lines, manually operated means at the central ofiice for rendering any of said central oflice' machines inoperative, said central ofiice machines being made operative Whena make signal flows through the cord circuit associated with said central ofiice machine and indicator means operating'while said central oflice machine is inoperative.

4. A printing telegraph system comprising, a plurality of subscribers lines, each of said lines normally terminating in one or more pin jacks at the central ofiice, relay means at said central oflice associated with each of said lines, each of said relay means having two windings and two sets of contacts, one of said windings being in series with the positive line current supply and the other winding being in series with the negative line current supply, one pair of said contacts being arranged to shunt one of said windings and the other pair arranged to operate an in'di-' cator when the said relay means is de-energized, a pressure key in each of said lines for de-energizing said relay, motor control means responsive to change in polarity of line current for rendering subscribersmachines inoperative. I

5. In a communication system, a main station, a plurality of branch stations, means for establishing a communication circuit between said main station and any oneof said branch statlons, means at said main station for renderlng inoperative the main station receivlng 7.. In a printing telegraph exchan e system,'a main station, a plurality of ranch stations, means comprising a single line conductor for establishing a printing telegraph circuit between said main station and any one of the branch stations, means at the said main station for rendering ino erative the main station printing telegrap means at said main station responsive to signaling impulses from the branch station to apparatus, and

render operative said main station printing telegraph apparatus. g

8. In a communication system, a main station, a plurality of branch stations, means comprising a single line conductor for establishing the communication circuit between said main station and any one of said branch stations, means at said main station for rendering inoperative the main station receiving and transmitting apparatus and means at said main station responsive to signaling impulses from the branch station to render operative said main station printer.

ALDER noonnnaY.

and transmitting apparatus and means at DISCLAIMER 1,773,952. Alder F. Connery, Brooklyn, N. Y. TELEGRAPH EXCHANGE SYSTEM. Patent dated August 26, 1930. Disclaimer filed February 1, 1935, by the assignee, Postal Telegraph-Cable Company.

Hereby enters this disclaimer to that part of claim 6 which is in the following Words, to Wit:

In a printing telegraph system comprising a plurality of printing telegraph subscribers lines terminating at a central oflice, manually controllable cord circuits at the central oflice for connection of any of said subscribers lines with any central ofiice printing telegraph machine, means responsive to said connection for changing the polarity of the line current, and motor controlled means at the subscribers office responsive to said change in polarity of line current.

[Ofiicial Gazette February 26, 1.985.] 

